Temperature and atmosphere control apparatus and method therefor



, c. E. P. SMITH 3,307,366 TEMPERATURE AND ATMOSPHERE CONTROL APPARATUS March 7, 1967 AND METHOD THEREFOR 2 Sheets-Sheet 1 Filed July 26, 19 65 INVENTOR CLIFFORD EP, SMITH ATTY.

March 7, 1967 c. E. P. SMITH 3,307,366

' TEMPERATURE AND ATMOSPHERE CONTROL APPARATUS AND METHOD THEREFOR Filed July 26, 1965 2 Sheets-Sheet :3

INVENTOR CLIFFORD 5F. SMITH BYW 2.77;

ATTY.

United States Patent 3,307,366 TEMPERATURE AND ATMOSPHERE CQNTROL APPARATUS AND METHOD THEREFOR Clifford E. P. Smith, Schererville, Ind., assignor to Pullman Incorporated, Chicago, 111., a corporation of Delaware Filed July 26, 1965, Ser. No. 474,665 29 Claims. (Cl. 625) This invention relates to means for controlling the temperature and gaseous mixture of a container and in particular relates to the control of the temperature and atmosphere of a container of a refrigerator as for instance as employed on a railway car for refrigerating perishable foods.

One of the problems in a refrigerating system employed in railway cars and the like is the change in temperature during transit from one section of the country to the other. For example, a refrigerated car may travel through an area having a temperature far below freezing so that internal refrigeration is not required and, in fact, the below freezing temperature is detrimental in that it causes the perishable items to freeze. This condition is particularly undesirable in the transporting of meat. In another section of the country having a warmer climate it is essential to maintain the internal compartment temperature at or near freezing temperature. Heretofore it has been com-mon practice to utilize a heat source of some type or other such as a charcoal burner for the purpose of maintaining the internal compartment temperature above that which freezes the perishable commodities in below freezing temperature areas. It has also been common practice to provide a liquid nitrogen system for the purpose of refrigerating or maintaining the temperature at or close to freezing during travel of a railroad car or other vehicle through warmer climates. Such systems as the liquid nitrogen type, while being adequate to provide the necessary cold temperatures still do not eliminate the necessity for a separate source of heat such as charcoal burners in the colder climates to prevent freezing of the perishables.

It is therefore a general object of this invention to provide a refrigeration system for maintaining temperatures in a container approximately the freezing temperature of water or 32 Fahrenheit.

A further object of this invention is to provide for the control not only of the temperature within a container but also allow for the introduction of sufiicient air or oxygen with the gaseous nitrogen present within the container in order to provide a suitable environment for the vegetables or meats.

Still another object of this invention is to provide means for raising the ambient temperatures within a container of a refrigeration system in colder climes and lowering the ambient temperature in warmer climes and for controlling the composition of the gases within the container to prevent deletrious effect on the meat and produce.

Another object of this invention is to use the kinetic energy of a cryogenic medium to heat or cool and control the refrigerant gaseous mixture in a container.

A further object of this invention is to provide refrigeration apparatus for a container and employing a vortex tube, commonly known as the Ranque Hilsch tube, as in US. Patent No. 1,952,281 to Ranque to regulate the temperature of the container.

Another object of this invention is to provide for the refrigeration apparatus as aforesaid a venturi means in conjunction with the vortex tube means for regulating the atmosphere within the container.

It is another object of this invention to provide a novel method for controlling the temperature and composition within a refrigerated container.

' eating tangentially with the inlet 28.

3,307,366 Patented Mar. 7, 1967 These and other objects will become apparent with reference to the following disclosure of appended claims, and attached drawings herein;

FIG. 1 is a diagrammatic view of a container provided with a temperature and atmosphere control apparatus;

FIG. 2 is an enlarged view showing the vortex heating means in conjunction with a composition control venturi means; and

FIG. 3 is a view of the vortex cooling means in conjunction with a venturi means.

With reference now to the drawings a refrigeration apparatus generally designated as 2 mounted for operation with a container or enclosure 4 and which may be for a truck trailer, a railroad car or the like. The refrigeration apparatus is provided with a nitrogen supply tank 6 containing liquid nitrogen 6a below 320 Fahrenheit. The tank 6 has an outlet 8 connecting with a temperature responsive valve unit 10, controlled by a pair of thermostat members 12 and 14. When the temperature drops below approximately 30-32 Fahrenheit (F) the lower portion of the valve unit is opened by the thermostat control 14 allowing liquid nitrogen to flow downwardly through the conduit 16 and into a conventional Cyrososorber vaporizer 18 which converts the liquid nitrogen to a vapor whence the vapors pass through line 20 into the heat exchanger 22 changing the temperature of the vapors which are at approximately 320 Fahrenheit to 30 Fahrenheit. From the heat exchanger 22 the warmed vapors pass through conduit 24 into the salvage heat exchanger 26 of the container or car 4 for raising the temperature of the nitrogen vapors from 30 Fahrenheit to 10 Fahrenheit, whence the vapors pass through conduit 28 into the vortex unit 30.

The vortex tube or unit 30 comprises an elongated tubular member 31 having a pair of opposed end hot and cold gas chambers 32 and 33 and a central housing 34 which is provided with a peripheral chamber 35 communi- The peripheral chamber 35 communicates with a central chamber 36 by way of reduced passage 37. The central chamber 36 has an outwardly diverging conical shape bore 38 communicating with the hot gas chamber 32 and has a reduced bore or orifice 39 communicating with its outwardly diverging bore 40 which communicates with the cold gas chamber 33. The hot gas chamber 32 is provided with an annular fiow restricting member 41 defining an annular passage 42 with the hot gas chamber 32. The nitrogen vapors entering from the conduit 28 enter the annular chamber 35 tangentially and are swirled in a helical path into the central chamber 36. That is, the inlet conduit 28 communicates with the reduced passage 37 communicating with the central chamber 36 to make the nitrogen pressurized vapors spin in the central chamber 36 creating a gaseous vortex pattern. The nitrogen vapor is actually given a rectilinear velocity parallel to the axis of the vortex tube, the rectilinear movement being combined with a gyratory movement about the axis of the tube. As the nitrogen vapor is moving away from the inlet pipe 28 its rectilinear velocity which is parallel to the axis of the tube increases and its angular velocity decreases so that the gas spreads along the wall of the tube 30. The molecules of the nitrogen gas are subjected to a pressure which is higher as they are a greater distance from the axis of the tube due to the action of centrifugal force.

' At the same time, the flow of the gas produces a substanof nitrogen gas passes through the restricted orifice 39 and out the cold gas chamber 33.

The hot vapors exiting from the left end of the vortex unit 30 enter the coils 43 heating the atmosphere A withing the container 4 whence the warm nitrogen vapors are passed or recirculated back to and within the salvage heat exchanger 26 to aid in maintaining the temperature within the exchanger 26 at about l Fahrenheit. The right end of the vortex unit 30 allows discharge of the cold nitrogen vapors into the outside atmosphere.

A Venturi unit 44 joins the coil 43 with the outside atmosphere to allow introduction of some of the outside air into the atmosphere A within the container 4 when the Venturi unit door 46 is manually opened. This provides for a better control of the composition of the atmosphere within the container and allows a normal color to the meats and vegetables Within the container. The Venturi door 46 is only opened when it is required to introduce sufficient oxygen within the container 4 and is particularly useful in controlling the composition of the atmosphere if it is to introduce the hot nitrogen vapors from the enclosure warming means or heat energy transference means or vortex unit 30 directly into the car by way of conduit 48, when the valve 50 is opened and the valve 52 leading to the coils 43 is closed. In order to prevent a build-up of excess pressure of the nitrogen vapors of the atmosphere A within the container 4, venting passage 54 is provided in the wall of the container 4 to allow vapors to escape from the container to the outside atmosphere. Pressure responsive valve 55 also admits atmosphere A into heat exchanger 26 for recirculation when pressure in container 4 exceeds a certain value.

When the container 4 is located in warmer climes the thermostat unit 12 allows the upper portion of the valve unit 10 to open and the lower thermostat unit 14 to close the lower end of the valve 10 allowing the liquid nitrogen in the container 6 and conduit 8 to pass only into the conduit 56 and through the refrigerating means or refrigeration coils 58 for cooling of the atmosphere A within the container because of the increased temperature outside of the container 4. The conduit 60 of the coils s passes through the wall 62 of the unit 4 to the optional heat exchanger 64 where the nitrogen vapors formed in the coils 58 may be further warmed to -l0 Fahrenheit or the vapors of the coil 58 may lead by line es directly to the conduit 66 depending on whether manually controlled valves 68 or '70 are opened or closed which will depend on the temperature of the outside atmosphere. The nitrogen vapors in the conduit 66 lead into the vortex unit or enclosure cooling means or heat energy transference means 30a that is joined by a Venturi unit 44a. The construction of the vortex or Hilsch tube unit 30a is constructed in the same manner as the unit 30 with the ex ception that the ends of the vortex unit 30a are reversed to allow hot air to be sent to the outside atmosphere through the vortex right end (see FIG. 1) and cold nitrogen vapors are allowed to be sent through the left end of the vortex unit 30a into atmosphere A of the compartment 4. The Venturi 44a functions in the same manner as the Venturi 44, that is, the atmosphere or air from outside the container is introduced into the atmosphere A of the compartment 4 when the manually controlled valve or door 46 is open and passes within the Venturi tubing 45 and around the end of the cold chamber 33 of the vortex unit 30a that forms a Venturi zone Z with the conduit part 45a having the first and second opposed diverging portions defining a reduced central portion with the outer end of the vortex tube in the zone Z to give the Venturi effect of sucking the outside atmosphere in with the exiting cold vapors in the right end of the vortex tube, the air and the cold nitrogen vapors being introduced into the compartment for lowering of the temperature of the container and controlling the atmosphere A in the warmer climates.

It is therefore seen that the novel inventive refrigeration arrangement disclosed above heats the container to approximately 34 when the external ambient temperature is a 30 Fahrenheit, the tank 6 containing the liquid nitrogen at 200# pressure and below 320 Fahrenheit, the supply of nitrogen to the heating system being controlled part way of the mercury liquid operated heat thermostat unit 10. When the container temperature drops to 30 Fahrenheit, the heat thermostat 14 opens the line to the vaporizer 18. Upon entry of the liquid nitrogen into the vaporizer 18 the oxygen in the air which is emitted to the vaporizer by way of an inlet is liquified, whereupon the liquid nitrogen becomes vaporized. The nitrogen vapors enter the heat exchanger 22 exposed to the atmosphere, the exchanger having sufficient surface area so that the vaporized nitrogen is heated to approximately the ambient temperature of 30 Fahrenheit, which then flows to the vortex tube 30 and recirculates through a salvage heat exchanger 26 which serves to add additional heat to the nitrogen vapor. The vortex tube, or commonly known as the Hilsch tube, is essentially a centrifugal heat separator which serves to discharge a warm stream of air at one end and a cool stream at the other end. The cold stream of the vortex tube is discharged outwardly of the container and the Warm stream internally thereof, and in this manner the container is maintained at approximately 30 Fahrenheit and should the temperature exceed 30 Fahrenheit the thermostat 12 will sense the change and close and prevent further operation of the heating system. When the warm stream is inserted into the container it is necessary to evacuate a corresponding amount of air or atmosphere in the container in order to prevent excessive pressure within the container through the passageway 54. The container atmosphere is also evacuated by way of pressure relief valve 55 which is connected by way of line 45a with the salvage heat exchanger 26 and the container atmosphere being heated will impart further heat into the nitrogen vapors in exchanger 26 so as to elevate the temperature of the nitrogen vapors from 30 Fahrenheit to 10 Fahrenheit and therefore the salvage heat exchanger 26 in efiect improves the efliciency of the heating system. The refrigenator system operates when the temperature exceeds approximately 30 Fahrenheit as sensed by the thermostat unit 10 to permit the liquid nitrogen into the refrigeration system, the liquid nitrogen passing through the heat exchanger 56 which is effective to control the temperature within the insulated container enclosure and from the heat exchanger the liquid nitrogen enters the vortex tube 30a with its hot vapor end disposed outwardly of the container 4 and the cold vapor end internally of the container 4. Such a reduction in temperature by the vortex tube decreases the on-time of the thermostat so that the amount of liquid nitrogen which is employed is correspondingly reduced. The vortex unit used to utilize the heat loss of the nitrogen upon normal cooling of the nitrogen results in about 20%25% efiiciency increase in the system when refrigerating the container and the vortex heating operation is about efiicient and the Venturi units prevent stagnation of air in the container promoting a turbulence and circulation of air in the container and oxygenate the container contents to about 5% oxygen and nitrogen atmosphere A with the result of preserving the meats and vegetables and other foods, in addition to the fact that the vortex arrangement allows warming of the container in the cool climes and cooling of the container in warm climes through the use of nitrogen or cryogenic medium normally utilized in such refrigeration system.

It will be appreciated that any number of vortex tubes or Venturi tubes may be employed depending on the size of the container and the temperature of the surrounding external atmosphere. The various values for the temperature and pressures and the various quantities stated may be varied and still be Within the scope of this invention. Other cryogenic media for example, inert gases, might be employed that would fall within the spirit of the invention. It will now -be apparent that the present invention provides a novel and essential temperature and atmosphere control system apparatus and method for regulation of the temperature and atmosphere within the enclosure. Although one embodiment of the invention has been illustrated and discussed in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the design and arrangement of the parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

What is claimed is:

1. An apparatus for regulating the temperature and atmosphere within an enclosure comprising a cryogenic medium, a vaporizer and heat exchanger means for converting the cryogenic medium from a liquid to a gas at an increased temperature, a vortex tube for receiving the heated vapors and having warm and cold vapor discharge openings, the cold discharge opening leading to the atmosphere and the Warm discharge opening leading to the interior of the container, a refrigerating means, a second vortex tube adapted to exit warm vapors and to introduce cold vapors into the container and connected with the refrigerating means, thermostatic means selectively connecting the cryogenic medium with the vaporizer and heat exchanger means and the refrigerating means when the temperature in the container is above or below a predetermined value and venting means adapted to introduce ambient surrounding air to the container for mixing with the vaporized cryogenic medium within the container.

2. An apparatus for controlling the temperature and composition Within a refrigerating container comprising a cryogenic medium, a vaporizer heat exchanger means for converting the medium from a liquid to a gas and elevating the temperature of same, enclosure warming means providing a heat energy separation of the vapors and discharging heated vapors within the container and cooling vapors outwardly of the. container supplied by said heat exchanger means, refrigerating means for the container, enclosure cooling means providing a heat energy separation of the vapors and discharging cooled vapors within the container and heated vapors outwardly of the container supplied by said refrigerating means, temperature regulating means disposed between the cryo genic medium and the heat exchanger means and refrigerating means and communicating with the heat exchanger means and the refrigerating means for-selectively operating either enclosure means, and means for introducing a controlled atmosphere within the conta-iner.

3. An apparatus for controlling the temperature within a refrigerating container comprising a tank for a cryogenic medium, a vaporizer heat exchanger means for converting the medium from a liquid to a gas and elevating the temperature of same, enclosure warming means communicating with the heat exchanger means and providing a heat energy separation of the vapors and discharging heated vapors within the container and cooling vapors outwardly of the container, refrigerating means for the container, temperature regulating means disposed between the tank and communicating with the heat exchanger and the refrigerating means for selectively operating either.

4. The invention according to claim 3 and the cryogenic medium comprising fluid nitrogen.

5. The invention according to claim 3 and the enclosure warming means comprising a vortex tube.

6. The invention according to claim 3 and means for introducing a controlled atmosphere within the container.

7. An apparatus for controlling the temperature and atmosphere Within a refrigerating enclosure comprising storage means for a cryogenic medium, vaporizing means for converting the medium from a liquid to a vapor, means for discharging the cryogenic vapors and changing the temperature within the enclosure and means for introducing oxygen into the enclosure with the cryogenic vapors and being operatively associated with the means for discharging the cryogenic vapors Within the enclosure, said means for discharging cryogenic vapors within the enclosure comprising vortex tube means having a cold vapor discharge opening within the enclosure and having a warm vapor discharge opening leading to the outside of the enclosure, and said means for introducing the oxygen comprising venting means operatively associated with the cold vapor discharging opening and communicating With the outside of the enclosure for introducing the oxygen into the enclosure with cold vapors discharging from the vortex tube means.

8. The invention according to claim 7 and said vaporizing means comprising refrigerating coil means disposed within the enclosure and connecting with the storage means for the cryogenic medium for cooling the vapors exiting from the cold vapor discharge opening.

9. An apparatus for controlling the temperature and atmosphere within a refrigerating enclosure comprising storage means for a cryogenic medium, vaporizing means for converting the medium from a liquid to a vapor, means for discharging the cryogenic vapors and changing the temperature within the enclosure and means for introducing oxygen into the enclosure with the cryogenic vapors and being operatively associated with the means for discharging the cryogenic vapors within the enclosure, said means for discharging cryogenic vapors within the enclosure comprising vortex tube means having a warm vapor discharge opening within the enclosure and having a cold vapor discharge opening leading to the outside of the enclosure, and said means for introducing oxygen comprising venting means operatively associated with the warm vapor discharging opening and communicating with the outside of the enclosure for introducing oxygen into the enclosure with the warm vapors discharging from the vortex tube means.

10. The invention according to claim 9 and said vaporizing means comprising heat exchanger means connecting with the storage means for the cryogenic medium and the vortex tube means for vaporizing and warming the cryogenic medium.

11. The invention according to claim 10 and said heat exchanger means including a salvage heat exchanger in vapor communication with the warm vapor discharge opening for supplying heat to the vapors supplied to the enclosure.

12'. The invention according to claim 9 and heating coil means connecting with the Warm vapor discharge opening and with said vaporizing means.

13. The invention according to claim 9 and pressure relief valve means for allowing warm vapors in the enclosure to enter the vaporizing means.

14. The method of controlling the temperature and atmosphere within a refrigerating enclosure comprising introducing a cryogenic fluid into the enclosure which is transformed from a liquid to a vapor and introducing the vapor into the enclosure and subjecting the vapor to a heat energy transference means whereby the exiting temperature of the vapor from the heat energy transference means and introduced into the enclosure is changed and introducing the vapor whose temperature has been changed into means for introducing oxygen within the enclosure and co-mingling of the cryogenic vapor with oxygen to produce a mixture of cryogenic vapor and the oxygen within the enclosure, said heat transferring means comprising vortex tube means.

15. The invention according to claim 14 and whereby said cryogenic vapor is exiting from said vortex tube means at an increased temperature for heating the inside of the enclosure.

16. The invention according to claim 14 and whereby said cryogenic vapor is exiting from said vortex tube means at a decreased temperature for cooling the inside of the enclosure.

17. The method of controlling the temperature and atmosphere within .a refrigerating enclosure comprising introducing a cryogenic fluid into the enclosure which is transformed from a liquid to a vapor and introducing the vapor into the enclosure and subjecting the vapor to a heat energy transference means whereby the exiting temperature of the vapor from the heat energy transference means and introduced into the enclosure is changed and introducing the vapor whose temperature has been changed into means for introducing oxygen within the enclosure and co-mingling of the cryogenic vapor with oxygen to produce a mixture of cryogenic vapor and the oxygen within the enclosure, said heat energy transferring means comprising a pair of vortex tubes, one of said vortex tubes allowing exiting of the cryogenic vapor into the enclosure at an elevated temperature and the other vortex tube allowing exiting of the cryogenic vapor into the enclosure at -a lower temperature.

18. The invention according to claim 17 and whereby the operation of each vortex tube is selectively operated by thermostatic means.

19. The invention according to claim 17 and wherein each vortex tube conducts the vapors to the means for co-mingling the cryogenic vapor and oxygen, the means for co-mingling c-ompring a venturi tube for each vortex tub-e.

20. The invention according to claim 17 and wherein thermostatic means selectively operates to transmit the vapor through one or other of the vortex units to maintain the temperature at generally 30 Fahrenheit to 34 Fahrenheit within the enclosure.

21. An apparatus for controlling the temperature and atmosphere within a refrigerating enclosure comprising a cryogenic medium, vaporizing means for converting the medium from a liquid to a vapor, means for discharging the cryogenic vapors and changing the temperature Within the enclosure and means for introducing oxygen into the enclosure with the cryogenic vapors and being operatively associated with the means for discharging the cryogenic vapors within the enclosure, said means for introducing oxygen comprising venturi means communicating with the air outside the enclosure and said cryogenic meduim comprising nitrogen.

22. The method of controlling the temperature and atmosphere within a refrigerating enclosure comprising introducing a cryogenic fluid into the enclosure which is transformed from a liquid to a vapor and introducing the vapor into the enclosure and subjecting the vapor to a heat energy transference means whereby the exiting temperature of the vapor from the heat energy transference means and introduced into the enclosure is changed and introducing the vapor whose temperature has been changed into means for introducing oxygen within the enclosure and co-mingling of the cryogenic vapor with oxygen to produce a mixture of cryogenic vapor and the oxygen Within the enclosure.

23. The invention according to claim 22 wherein said cryogenic fluid comprises nitrogen.

24. The invention according to claim 22 and said means for introducing oxygen comprising venturi means coupled with said heat energy transference means for introducing a mixture of the cryogenic vapor and the oxygen into the enclosure.

25. The invention according to claim 22 and whereby such mixture of cryogenic vapor and oxygen within the enclosure comprises approximately to 99% nitrogen and 1% to 10% oxygen.

26. The invention according to claim 22 and the oxygen being supplied by the outside atmosphere surrounding the enclosure.

27. An apparatus for controlling the temperature and atmosphere within a refrigerating enclosure comprising a cryogenic medium, means for converting the medium from a liquid to a vapor, heat energy transference means for discharging the cryogenic vapors at a changed temperature within the enclosure, and means for introducing oxygen bearing means into enclosure with the cryogenic vapors and operatively associated with the means for discharging the cryogenic vapors within the enclosure.

28. The invention according to claim 27 and said means for discharging the cryogenic vapors within the enclosure comprising vortex tube means having a cold vapor discharge opening and having a warm vapor discharge opening.

29-. The invention according to claim 27 and said means for introducing the oxygen bearing means into the enclosure with the cryogenic vapors comprising venturi tube means.

References Cited by the Examiner UNITED STATES PATENTS 2,089,428 8/1937 Ross 62-52 2,873,582 2/1959 Green 625 2,893,214 7/1959 Hendal 625 2,943,459 7/ 1960 Rind 6252 2,984,994 5/1961 Hankins 6250 2,990,695 7/ 1961 Lefiingwell 6252 3,026,681 3/1962 Green 625 3,058,317 10/1962 Putman 6252 3,064,448 11/1962 Whittington 62-5 2 3,121,999 2/1964 Kasbohm 6250 3,241,329 3/1966 Fritch 6252 WILLIAM J. WYE, Primary Examiner. 

1. AN APPARATUS FOR REGULATING THE TEMPERATURE AND ATMOSPHERE WITHIN AN ENCLOSURE COMPRISING A CRYOGENIC MEDIUM, A VAPORIZER AND HEAT EXCHANGER MEANS FOR CONVERTING THE CRYOGENIC MEDIUM FROM A LIQUID TO A GAS AT AN INCREASED TEMPERATURE, A VORTEX TUBE FOR RECEIVING THE HEATED VAPORS AND HAVING WARM AND COLD VAPOR DISCHARGE OPENINGS, THE COLD DISCHARGE OPENING LEADING TO THE ATMOSPHERE AND THE WARM DISCHARGE OPENING LEADING TO THE INTERIOR OF THE CONTAINER, A REFRIGERATING MEANS, A SECOND VORTEX TUBE ADAPTED TO EXIT WARM VAPORS AND TO INTRODUCE COLD VAPORS INTO THE CONTAINER AND CONNECTED 